plasma protein - any of the proteins in blood plasma

factor I, fibrinogen - a protein present in blood plasma; converts to fibrin when blood clots

factor II, prothrombin - a protein in blood plasma that is the inactive precursor of thrombin

factor III, thrombokinase, thromboplastin - an enzyme liberated from blood platelets that converts prothrombin into thrombin as blood starts to clot

calcium ion, factor IV - ion of calcium; a factor in the clotting of blood

accelerator factor, factor V, proaccelerin, prothrombin accelerator - a coagulation factor

cothromboplastin, factor VII, proconvertin, stable factor - a coagulation factor formed in the kidney under the influence of vitamin K

antihaemophilic factor, antihaemophilic globulin, antihemophilic factor, antihemophilic globulin, factor VIII, Hemofil - a coagulation factor (trade name Hemofil) whose absence is associated with hemophilia A

Christmas factor, factor IX - coagulation factor whose absence is associated with hemophilia B

factor X, prothrombinase - coagulation factor that is converted to an enzyme that converts prothrombin to thrombin in a reaction that depends on calcium ions and other coagulation factors

factor XI, plasma thromboplastin antecedent - coagulation factor whose deficiency results in a hemorrhagic tendency

factor XII, Hageman factor - coagulation factor whose deficiency results in prolongation of clotting time of venous blood

factor XIII, fibrinase - in the clotting of blood thrombin catalyzes factor XIII into its active form (fibrinase) which causes fibrin to form a stable clot